The field of the invention is water treatment, and the invention relates more particularly to processes for removing radon from drinking water.
It is well known that radon can be removed from drinking water by aeration of the water. The radon gas, being highly volatile, tends to be released from the water particularly when the water is aerated. While the present invention is directed toward radon removal, it is, of course, useful for removing other volatile contaminants present in potable water.
Various pieces of equipment have been suggested for radon removal such as that in U.S. Pat. No. 4,371,383. This process involves spraying water into a tank which has splash plates. An air blower circulates air through the spray of water and exhausts the air to the atmosphere. A similar approach is shown in U.S. Pat. No. 4,869,832 where water from a well is sprayed onto the top of a packed column and trickles downwardly through the column. An air blower moves air upwardly along the column and exhausts the air at the top of the column to the atmosphere. A similar process is shown in U.S. Pat. No. 5,045,215. This equipment uses a horizontal tray with baffles. As the water moves downwardly through this device, air is blown upwardly through the perforations frothing the water on the trays and evaporating the radon and other contaminants from the water. The contaminants are then vented to the atmosphere.
While such systems are effective to remove radon and other volatile contaminants, they merely vent these contaminants to the atmosphere. Furthermore, the water in the vessels is maintained at essentially atmospheric pressure during the treatment process and must be repressurized to bring it back to line pressure for distribution.